Lubricating compositions having a mixed dispersant additive package

ABSTRACT

The instant disclosure generally relates to lubricating compositions having an oil of lubricating viscosity and a mixed dispersant additive package. The mixed dispersant additive package can include an acylated poly(1-olefin)-based dispersant and a poly-isobutylene succinimide dispersant where the ratio of the acylated poly(1-olefin)-based dispersant to the polyisobutylene succinimide dispersant in the lubricating composition is from 3:1 to 1:3.

FIELD

The instant disclosure generally relates to lubricating compositions having an oil of lubricating viscosity and a mixed dispersant additive package. The mixed dispersant additive package includes an acylated poly(1-olefin)-based dispersant and an acylated polyisobutylene-based dispersant.

BACKGROUND

Dispersants have been employed in lubricant and fuel formulations to provide protection against and to stabilize dirt and sludge that accumulate in the formulations during ordinary use. Dispersants typically have hydrophilic heads and hydrophobic tails and exhibit the properties of surfactants. The hydrophilic heads have an affinity for dirt and sludge, while the hydrophobic tails have an affinity for the base stocks of the lubricant and fuel formulations.

A common class of dispersants used in lubricant or fuel formulations is prepared by functionalizing polyisobutylene (PIB) with maleic anhydride, followed by reaction with polyamines. These dispersants work well for typical lubricant and fuel formulations.

New lubricating compositions are formulated to meet higher automobile fuel economy standards, longer oil drain intervals, and greater operating severity. This need may require the use of even higher levels of dispersants and/or lower lubricant base stock viscosity. The use of higher levels of PIB-based dispersants, however, may significantly increase the viscosity of lubricant compositions and render it difficult to attain lower motor oil viscosity grades, e.g., 0W-20 and 0W-30. Lower viscosity grades for motor oil are particularly important in meeting fuel economy guidelines.

An alternative to increasing dispersant levels is to use lower viscosity base stocks. However, the use of such lower viscosity base stocks can result in higher volatility (loss of oil) and reduced lubricant oil film and wear protection on internal engine surfaces.

To address the increased viscosity related to the use of PIB-based dispersants, formulators are using various alternatives to the PIB-based dispersants. One such alternative dispersant type is polyalphaolefin (PAO)-based dispersants.

U.S. Patent Application Publication No. 2012/0264665 (Wu, published 18 Oct. 2012) discloses a lubricant blend including one or more lubricant stocks and one or more dispersants chosen from a polyalphaolefin succinimide, a polyalphaolefin succinamide, a polyalphaolefin acid ester, a polyalphaolefin oxazoline, a polyalphaolefin imidazoline, a polyalphaolefin succinamide imidazoline, and combinations thereof, present at 2 to 20 wt % based on the total weight of the blend.

Although, PAO-based dispersants may help formulate a lubricating composition at lower viscosity over a PIB-based dispersant, PAO-based dispersants do not provide the same level of deposit control and overall cleanliness of a lubricating composition as a PIB-based dispersant.

Thus, there is a need for a dispersant that provides lubricant formulations with effective deposit control and overall cleanliness at low viscosity grade engine oil applications.

BRIEF SUMMARY

The instant disclosure relates to a lubricating composition having a mixed dispersant additive package. The lubricating composition includes an oil of lubricating viscosity and from 2 to 20 wt % of a dispersant additive package where the mixed dispersant additive package includes an an acylated poly(1-olefin)-based dispersant, where the poly(1-olefin) is comprised of at least 75 mole percent of a C6 to C18 hydrocarbyl and a polyisobutylene-based dispersant. The ratio of the acylated poly(1-olefin)-based dispersant to the polyisobutylene succinimide dispersant in the lubricating composition is from 3:1 to 1:3, or 2:1 to 1:2, or 3:2 to 2:3.

The instant disclosure further relates to a lubricating composition having an oil of lubricating viscosity and a dispersant additive package where the mixed dispersant additive package includes from 2 to 8 wt % of an acylated poly(1-olefin)-based dispersant, where the poly(1-olefin) is comprised of at least 75 mole percent of a C6 to C18 hydrocarbyl and from 1 to 6 wt % of a polyisobutylene-based dispersant, where the ratio of the acylated poly(1-olefin)-based dispersant to the polyisobutylene succinimide dispersant in the lubricating composition is from 2:1 to 1:2.

The instant disclosure further relates to a lubricating composition having an oil of lubricating viscosity and a dispersant additive package where the mixed dispersant additive package includes from 2 to 8 wt % of polydecene succinimide dispersant and from 1 to 6 wt % of a polyisobutylene-based dispersant, where the ratio of the acylated poly(1-olefin)-based dispersant to the polyisobutylene succinimide dispersant, where the ratio of polydecene succinimide dispersant to the polyisobutylene dispersant is from 2:1 to 1:2.

The instant disclosure further relates to a lubricating composition having an oil of lubricating viscosity and a dispersant additive package where the mixed dispersant additive package includes from 2 to 8 wt % of polydecene succinimide dispersant and from 1 to 6 wt % of a polyisobutylene-based dispersant, where the ratio of the acylated poly(1-olefin)-based dispersant to the polyisobutylene succinimide dispersant, where the ratio of polydecene succinimide dispersant to the polyisobutylene dispersant is from 2:1 to 1:2 and the lubricating composition has a has a kinematic viscosity at 100° C. from 6 to 10 cSt (mm2/s) and a kinematic viscosity at 40° C. from 40 to 47 cSt (mm2/s) and a high shear viscosity (HTHS) of less than 3 mPa-s.

The instant disclosure further relates to method of lubricating an internal combustion engine by supplying to an internal combustion engine a lubricating composition including an oil of lubricating viscosity and from 2 to 20 wt % of a dispersant additive package where the mixed dispersant additive package includes an an acylated poly(1-olefin)-based dispersant, where the poly(1-olefin) is comprised of at least 75 mole percent of a C6 to C18 hydrocarbyl and a polyisobutylene-based dispersant. The ratio of the acylated poly(1-olefin)-based dispersant to the polyisobutylene succinimide dispersant in the lubricating composition is from 3:1 to 1:3, or 2:1 to 1:2, or 3:2 to 2:3.

In another embodiment, the instant disclosure relates to a method of lubricating an internal combustion engine by supplying to an internal combustion engine a lubricating composition including an oil of lubricating viscosity and from 2 to 8 wt % of an acylated poly(1-olefin)-based dispersant, where the poly(1-olefin) is comprised of at least 75 mole percent of a C6 to C18 hydrocarbyl and from 1 to 6 wt % of a polyisobutylene-based dispersant, where the ratio of the acylated poly(1-olefin)-based dispersant to the polyisobutylene succinimide dispersant in the lubricating composition is from 2:1 to 1:2.

In another embodiment, the instant disclosure relates to a method of lubricating an internal combustion engine by supplying to an internal combustion engine a lubricating composition including an oil of lubricating viscosity and a dispersant additive package where the mixed dispersant additive package includes from 2 to 8 wt % of polydecene succinimide dispersant and from 1 to 6 wt % of a polyisobutylene-based dispersant, where the ratio of the acylated poly(1-olefin)-based dispersant to the polyisobutylene succinimide dispersant, where the ratio of polydecene succinimide dispersant to the polyisobutylene dispersant is from 2:1 to 1:2.

In another embodiment, the instant disclosure relates to a method of lubricating an internal combustion engine by supplying to an internal combustion engine a lubricating composition including an oil of lubricating viscosity and a dispersant additive package where the mixed dispersant additive package includes from 2 to 8 wt % of polydecene succinimide dispersant and from 1 to 6 wt % of a polyisobutylene-based dispersant, where the ratio of the acylated poly(1-olefin)-based dispersant to the polyisobutylene succinimide dispersant, where the ratio of polydecene succinimide dispersant to the polyisobutylene dispersant is from 2:1 to 1:2 and the lubricating composition has a has a kinematic viscosity at 100° C. from 6 to 10 cSt (mm2/s) and a kinematic viscosity at 40° C. from 40 to 47 cSt (mm2/s) and a high shear viscosity (HTHS) of less than 3 mPa-s.

DETAILED DESCRIPTION

The instant disclosure relates to lubricating compositions having a dispersant additive package and methods for lubricating an internal combustion engine. Lubricating compositions disclosed herein may include an oil of lubricating viscosity and from 2 to 20 wt % of a dispersant additive package including an acylated poly(1-olefin)-based dispersant, where the 1-olefin is comprised of at least 75 mole percent of a C₆ to C₁₈ hydrocarbyl, and an acylated polyisobutylene-based dispersant. In one embodiment, the lubricating composition may include one or more additional additives, as disclosed herein.

Oils of Lubricating Viscosity

As used herein, an oil of lubricating viscosity may include natural and synthetic oils, oil derived from hydrocracking, hydrogenation, and hydrofinishing, unrefined, refined, re-refined oils or mixtures thereof. A more detailed description of unrefined, refined and re-refined oils is provided in International Publication WO2008/147704, paragraphs [0054] to [0056] (a similar disclosure is provided in US Patent Application 2010/197536, see [0072] to [0073]). A more detailed description of natural and synthetic lubricating oils is described in paragraphs [0058] to [0059] respectively of WO2008/147704 (a similar disclosure is provided in US Patent Application 2010/197536, see [0075] to [0076]). The cited portions of both references are incorporated herein. Synthetic oils may also be produced by Fischer-Tropsch reactions and typically may be hydroisomerised Fischer-Tropsch hydrocarbons or waxes. In one embodiment oils may be prepared by a Fischer-Tropsch gas-to-liquid synthetic procedure as well as other gas-to-liquid oils.

Suitable oils may be produced from biological, i.e. natural, sources or by bio-engineered processes. This includes both natural occurring oils, such as vegetable oils and triglyceride oils that may be further refined or purified by standard processes, and those oils that may be derived by biological conversion of a natural chemical into oil directly or by bio-formation of building block pre-cursor molecules capable of being further converted into oil by known processes.

Oils of lubricating viscosity may also be defined as specified in April 2008 version of “Appendix E—API Base Oil Interchangeability Guidelines for Passenger Car Motor Oils and Diesel Engine Oils”, section 1.3 Sub-heading 1.3. “Base Stock Categories”. The API Guidelines are also summarised in U.S. Pat. No. 7,285,516 (see column 11, line 64 to column 12, line 10), which are incorporated herein by reference.

In one embodiment the oil of lubricating viscosity may be an API Group I to IV mineral oil, an ester or a synthetic oil, or mixtures thereof. In one embodiment the oil of lubricating viscosity may be an API Group II, Group III, Group IV mineral oil, an ester or a synthetic oil, or mixtures thereof.

The amount of the oil of lubricating viscosity present is typically the balance remaining after subtracting from 100 wt % the sum of the amount of the dispersant additive package according to the instant disclosure and additional, if any, additives.

The lubricating composition may be in the form of a concentrate and/or a fully formulated lubricant. If the lubricating composition of the instant disclosure (comprising the dispersant additive package disclosed herein and, optionally, other additives) is in the form of a concentrate which may be combined with additional oil to form, in whole or in part, a finished lubricant, the ratio of these additives to the oil of lubricating viscosity and/or to diluent oil include the ranges of 1:99 to 99:1 by weight, or 80:20 to 10:90 by weight. Typically, the lubricating composition of the invention comprises at least 50 wt %, or at least 60 wt %, or at least 70 wt %, or at least 80 wt % of an oil of lubricating viscosity.

In the present disclosure, the lubricating composition can include a base oil having a kinematic viscosity measured at 100° C. of 2.4 m²/s to 6.4 m²/s. In some embodiments, the kinematic viscosity is from 4.0 m²/s to 5.0 m²/s or from 5.2 m²/s to 5.8 m²/s or from 6.0 m²/s to 6.5 m²/s. In other embodiments, the kinematic viscosity is 6.2 m²/s or 5.6 m²/s or 4.6 m²/s.

The Dispersant Additive Package

Lubricating composition disclosed herein includes a dispersant additive package having a first dispersant comprising an acylated poly(1-olefin)-based dispersant and a second dispersant comprising an acylated polyisobutylene-based dispersant.

As stated above, the first dispersant comprises an acylated poly(1-olefin)-based dispersant. The first dispersant is prepared from a poly(1-olefin). Poly(1-olefin)'s useful as feedstocks in forming the first dispersant are those derived from oligomerization or polymerization of C₆ to C₁₈ 1-olefins. Such 1-olefins include 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, hexadecane, heptadecene, 1-octadecene, and mixtures thereof. Feedstocks containing a mixture of two or more of the foregoing monomers as well as other hydrocarbons are typically employed when manufacturing PAOs commercially. The PAO may take the form of dimers, trimers, tetramers, polymers, and the like. In one illustrative embodiment, the α-olefin includes 1-decene.

In one embodiment, the poly(1-olefin) includes at least 75 mole percent of a C₆ to Cis hydrocarbyl. In another embodiment, the C₆ to C₁₈ hydrocarbyl is a C₆ to C₁₈ 1-olefin. In another embodiment, the poly(1-olefin) includes at least 80 mole percent of a C₆ to C₁₈ hydrocarbyl. In some embodiments, the poly(1-olefin) includes at least 85 mole percent of a C₆ to C₁₈ hydrocarbyl. In another embodiment, the poly(1-olefin) includes at least 90 mole percent of a C₆ to C₁₈ hydrocarbyl. In one embodiment, the poly(1-olefin) includes at least 100 mole percent of a C₆ to C₁₈ hydrocarbyl. In one embodiment, the 1-olefin is 1-decene.

In one embodiment, the poly(1-olefin) includes at least 75 mole percent of a C₈ to C₁₂ hydrocarbyl. In another embodiment, the poly(1-olefin) includes at least 80 mole percent of a C₈ to C₁₂ hydrocarbyl. In yet another embodiment, the poly(1-olefin) includes at least 85 mole percent of a C₈ to C₁₂ hydrocarbyl. In another embodiment, the poly(1-olefin) includes at least 90 mole percent of a C₈ to C₁₂ hydrocarbyl. In one embodiment, the poly(1-olefin) includes at least 100 mole percent of a C₈ to C₁₂ hydrocarbyl. In one embodiment, the poly(1-olefin) includes at least 75 mole percent of a C₈ to C₁₂ 1-olefin. In another embodiment, the poly(1-olefin) includes at least 75 mole percent of 1-decene.

The poly(1-olefin) used to prepare the first dispersant may have a M_(n)(number-average molecular weight) of 400 to 10,000. In one embodiment, the poly(1-olefin) can have a M_(n) of 500 to 9,000. In another embodiment, the poly(1-olefin) has a M_(n) of 500 to 7,500. In one embodiment, the poly(1-olefin) has a M_(n) of 500 to 6,000. In one embodiment, the poly(1-olefin) has a M_(n) of 500 to 4,400. In another embodiment, the poly(1-olefin) has a M_(n) of 400 to 1,000. In yet another embodiment, the poly(1-olefin) has a M_(n) of 400 to 800.

The first dispersant can be selected from a polyalphaolefin succinimide, a polyalphaolefin succinamide, a polyalphaolefin acid ester, a polyalphaolefin oxazoline, a polyalphaolefin imidazoline, a polyalphaolefin succinamide imidazoline, and combinations thereof. In one embodiment, the first dispersant is a polyalphaolefin succinimide. In another embodiment, the first dispersant is a polydecene succimide.

The first dispersant may also be described as having a total base number (“TBN”) calculated on an oil-free basis. Unless otherwise stated, all TBN's are herein described on an oil-free basis and are defined as KOH/g. The TBN of the first dispersant can be in a range of from 3 to 100. In another embodiment, the TBN of the first dispersant is from 5 to 20. In yet another embodiment, the TBN of the first dispersant is from 10 to 60.

The polyalphaolefin suitable for use in first dispersant can be prepared by oligomerization or polymerization of C₆ to C₁₈ 1-olefins in the presence of an activated metallocene catalyst. Such a process is described in, for example, WO 2007/011462 A1, WO 2007011459 A1, WO 2007/011973 A1, and U.S. Patent Application Publication No. 2012/0264665 all of which are incorporated herein by reference.

The polyalphaolefins described herein may be reacted with an acylating agent, i.e. an ethylenically unsaturated carbonyl compound, to form an acylated poly(1-olefin) which may be further functionalized with an amine or alcohol to form a suitable dispersant. Suitable acylating agents include maleic anhydride or a reactive equivalent thereof (such as an acid or ester), fumaric acid, itaconic acid, itaconic anhydride, citraconic acid, citaconic anhydride, and cinnamic acid as well as other ethylenically unsaturated acids such as acrylic or methacrylic acid; and their reactive equivalents.

In one embodiment, the polyalphaolefin may be reacted with maleic anhydride (MA) to form a polyalphaolefin succinic anhydride (PAO-SA). The ratio of the polyalphaolefin to maleic anhydride (“succination ratio”) can be from 1:1 to 1:2. In one embodiment, the succination ratio is 1:1 (“monosuccination”). In another embodiment, the succination ratio is 1:2. It is understood that mixtures of mono-succinated polyolefins and di-succinated polyolefins will provide a succination ratio between 1:1 and 1:2. In one embodiment, the succination ratio may be 1:1 to 1:1.5, or 1:1 to 1.3.

Those skilled in the art will understand that not all of the polymer present in the reaction mixture with maleic anhydride will react to form acylated product. The conversion of the polymer to acylated product can be expressed as a number between one and two, where a conversion of 1 would indicate that, of the polymer that reacted, it only reacted with one mole of maleic anhydride (to form a mono-succan). An acylating agent with a conversion of 2 would indicate that two equivalents of maleic anhydride were added per reacted polymer chain (to form a di-succan). The vast majority of manufactured acylating agents contain a mixture of mono and di-succan, such that the conversion ratio can be represented as a number between 1 and 2, such as 1.2, 1.5 or 1.7. The higher the conversion number, the higher the percentage of disuccan is present in the mixture. In this context, the conversion calculation excludes the unreacted polymer. This conversion represents the average number of times that each polymer chain has reacted with the acylating agent.

The PAO-SA can be subsequently reacted with one or more of polyamines, aminoalcohols, and alcohols/polyols to form polyalphaolefin succinimide, polyalphaolefin succinamides, including diamides, polyalphaolefin succinimide/acid, polyalphaolefin succinimide ester, polyalphaolefin succinic diesters, polyalphaolefin succinic diacids, and polyalphaolefin succinic acid ester. Suitable amine and alcohol compounds are described in more detail below. Other polyalphaolefin-based dispersants are also contemplated, such as polyalphaolefin oxazoline, polyalphaolefin imidazoline, polyalphaolefin succinimide imdazoline, and mixtures thereof. PAO species contemplated in this disclosure are further described in U.S. 2012/0264665, the sections describing such species is hereby incorporated herein by reference.

The poly(1-olefin) dispersant may be post-treated by conventional methods by a reaction with any of a variety of agents. Among these are boron compounds (such as boric acid), urea, thiourea, dimercaptothiadiazoles, carbon disulphide, aldehydes, ketones, carboxylic acids such as terephthalic acid, hydrocarbon-substituted succinic anhydrides, maleic anhydride, nitriles, epoxides, and phosphorus compounds. In one embodiment, the post-treated dispersant is borated. In one embodiment, the post-treated dispersant is reacted with dimercaptothiadiazoles. In one embodiment, the post-treated dispersant is reacted with phosphoric or phosphorous acid. In one embodiment, the post-treated dispersant is reacted with terephthalic acid and boric acid (as described in US Patent Application US2009/0054278, which is incorporated herein by reference in its entirety).

The dispersant additive package also includes a second dispersant. The second dispersant includes a polyisobutylene succinimide dispersant. The polyisobutylene (“PIB”) succinimide dispersant can be a “conventional” PIB or a high vinylidene PIB. The difference between a conventional polyolefin and a high vinylidene polyolefin can be illustrated by reference to the production of PIB. In a process for producing conventional PIB, isobutylene is polymerized in the presence of AlCl₃ to produce a mixture of polymers comprising predominantly trisubstituted olefin (III) and tetrasubstituted olefin (IV) end groups, with only a very small amount (for instance, less than 20 percent) of chains containing a terminal vinylidene group (I). In an alternative process, isobutylene is polymerized in the presence of BF₃ catalyst to produce a mixture of polymers comprising predominantly (for instance, at least 70 percent) terminal vinylidene groups, with smaller amounts of tetrasubstituted end groups and other structures. The materials produced in the alternative method, sometimes referred to as “high vinylidene PIB,” are also described in U.S. Pat. No. 6,165,235, which is incorporated herein by reference in its entirety. In one embodiment, the polyisobutylene-based dispersant is a conventional polyisobutylene-based dispersant. In another embodiment, the polyisobutylene-based dispersant is a high or mid vinylidene succinimide dispersant. The polyisobutylene-based dispersant used herein is generally known in the art.

The polyisobutylene-based acylating agent may be prepared/obtained/obtainable from reaction with maleic anhydride by an “ene” or “thermal” reaction. The “ene” reaction mechanism and general reaction conditions are summarized in “Maleic Anhydride”, pages, 147-149, Edited by B. C. Trivedi and B. C. Culbertson and Published by Plenum Press in 1982. The polyisobutylene-based dispersant prepared by a process that includes an “ene” reaction includes a dispersant having a carbocyclic ring present on less than 50 mole %, or 0 to less than 30 mole % b, or 0 to less than 20 mole %, or 0 mole % of the dispersant molecules. The “ene” reaction may have a reaction temperature of 180° C. to less than 300° C., or 200° C. to 250° C., or 200° C. to 220° C.

The polyisobutylene-based acylating agent may also be obtained/obtainable from a chlorine-assisted process, often involving Diels-Alder chemistry, leading to formation of carbocyclic linkages. The process is known to a person skilled in the art. The chlorine-assisted process may produce an acylating agent having a carbocyclic ring present on 50 mol % or more, or 60 to 100 mol % of the molecules. Both the thermal and chlorine-assisted processes are described in greater detail in U.S. Pat. No. 7,615,521, columns 4-5 and preparative examples A and B.

The polyisobutylene-based acylating agent may also be prepared/obtained/obtainable from a free radical process, wherein the acylating agent is reacted with polyisobutylene in the presence of a free radical initiator. Free radical processes of this sort are well known in the art and may be carried out in the presence of additional alpha-olefin.

The polyisobutylene-based acylating agent can be obtained from reacting polyisobutylene with an acylating agent, i.e., an ethylenically unsaturated carbonyl compound, to form an acylated polyisobutylene which may be further functionalized with an amine or alcohol to form a suitable dispersant. Suitable acylating agents include maleic anhydride or a reactive equivalent thereof (such as an acid or ester), fumaric acid, itaconic acid, itaconic anhydride, citraconic acid, citaconic anhydride, and cinnamic acid as well as other ethylenically unsaturated acids such as acrylic or methacrylic acid; and their reactive equivalents. In one embodiment, polyisobutylene may be reacted with maleic anhydride to form acylated product with a conversion between 1 and 2. In one embodiment, the monosuccan is reacted with an amine so that the intended product comprises a mixture wherein all of the anhydride present in the acylating agent has been converted to imide.

The polyisobutylene-based dispersant may have a carbonyl to nitrogen ratio (CO:N ratio) of 5:1 to 1:10, 2:1 to 1:10, or 2:1 to 1:5, or 2:1 to 1:2. In one embodiment the dispersant may have a CO:N ratio of 2:1 to 1:10, or 2:1 to 1:5, or 2:1 to 1:2, or 1:1.4 to 1:0.6.

The polyisobutylene-based dispersant may also be post-treated by conventional methods by a reaction with any of a variety of agents. Among these are boron compounds (such as boric acid), urea, thiourea, dimercaptothiadiazoles, carbon disulphide, aldehydes, ketones, carboxylic acids such as terephthalic acid, hydrocarbon-substituted succinic anhydrides, maleic anhydride, nitriles, epoxides, and phosphorus compounds. In one embodiment, the post-treated dispersant is borated. In one embodiment, the post-treated dispersant is reacted with dimercaptothiadiazoles. In one embodiment, the post-treated dispersant is reacted with phosphoric or phosphorous acid. In one embodiment, the post-treated dispersant is reacted with terephthalic acid and boric acid (as described in US Patent Application US2009/0054278).

In one such post-treatment, the polyisobutylene-based dispersant may be borated using one or more of a variety of agents selected from the group consisting of the various forms of boric acid (including metaboric acid, HBO₂, orthoboric acid, H₃BO₃, and tetraboric acid, H₂B₄O₇), boric oxide, boron trioxide, and alkyl borates. In one embodiment the borating agent is boric acid which may be used alone or in combination with other borating agents. Methods of preparing borated dispersants are known in the art. The borated dispersant may be prepared in such a way that they contain 0.1 weight % to 2.5 weight % boron, or 0.1 weight % to 2.0 weight % boron or 0.2 to 1.5 weight % boron or 0.3 to 1.0 weight % boron.

The isobutylene polymer can have a number average molecular weight (Mn) of from 500 to 3,000. In another embodiment, the Polyisobutylene-based dispersant has a Mn of from 700 to 2,000. In one embodiment, the isobutylene polymer has a Mn of from 900 to 1,500. In another embodiment, the isobutylene polymer has a Mn of from 1,000 to 1,200.

The polyisobutylene-based dispersant for use as the second dispersant can further be described as having a TBN. In one embodiment, the Polyisobutylene-based dispersant has a TBN of from 5 to 50. In another embodiment, the Polyisobutylene-based dispersant has a TBN of from 10 to 40. In yet another embodiment, the Polyisobutylene-based dispersant has a TBN of from 15 to 30.

The polyolefin-based dispersant and the polyisobutylene-based dispersant may be a derivative of an aliphatic polyamine, or mixtures thereof. The aliphatic polyamine may be aliphatic polyamine such as an ethylenepolyamine, a propylenepolyamine, a butylenepolyamine, or mixtures thereof. In one embodiment, the aliphatic polyamine may be ethylenepolyamine. In one embodiment, the aliphatic polyamine may be selected from the group consisting of ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, polyamine still bottoms, and mixtures thereof.

The polyolefin-based dispersant and the polyisobutylene-based dispersant may be derivatives of an aromatic amine, an aromatic polyamine, or mixtures thereof. The aromatic amine may be 4-aminodiphenylamine (ADPA) (also known as N-phenylphenylenediamine), derivatives of ADPA (as described in United States Patent Publications 2011/0306528 and 2010/0298185), a nitroaniline, an aminocarbazole, an amino-indazolinone, an aminopyrimidine, 4-(4-nitrophenylazo)aniline, or combinations thereof. In one embodiment, the first or second dispersant is a derivative of an aromatic amine wherein the aromatic amine has at least three non-continuous aromatic rings.

In one embodiment, the polyamine may contain at least one sterically hindered amine group. In one aspect, the polyamine contains a primary amino group for reaction with the acylating agent and at least one additional sterically hindered amine. In one aspect, the polyamine contains a terminal primary amine moiety that reacts with the polyolefin substituted acylating agent and at least one sterically hindered amine, one of which is a terminal head group. By terminal head group is meant is that a sterically hindered amine moiety is situated at a position that is distal to the primary amine moiety (i.e., situated at the distal terminus of the polyamine).

In one aspect, the sterically hindered polyamine reactant conforms to the formula:

wherein R₁ independently is a linear or branched hydrocarbylene moiety containing 2 to 10 carbon atoms (preferably 2 to 6); X is O or N(R₂), where R₂ is independently selected from hydrogen, substituted and unsubstituted hydrocarbyl group (C₁ to C₁₀ alkyl, C₁ to C₁₀ hydroxy substituted alkyl); n is 0 or 1 to 10; R₃ and R₄ independently represent a substituted or unsubstituted hydrocarbyl group (can be alicyclic and aromatic) containing 5 to 30 carbon atoms, subject to the proviso that the total number of carbon atoms contained in R₃ and R₄ is at least 10; R₃ and R₄ taken together with the nitrogen atom to which they are attached represents a substituted or unsubstituted monocyclic or multicyclic ring structure (non-aromatic or aromatic) containing at least 4 carbon atoms, wherein said ring structures optionally contain at least one additional heteroatom (e.g., selected from O, N, S and carbonyl) for purposes herein carbonyl will be defined as a heteroatom), subject to the proviso that when R² and R³ are taken together with the nitrogen atom to which they are attached represent a monocyclic ring containing 4 or 5 carbon atoms, the two carbon atoms directly attached to said nitrogen atom is substituted with a hydrocarbyl moiety containing 1 to 5 carbon atoms. In one aspect, R₃ and R₄ are independently selected from neopentyl, 2-ethylhexyl, 2-propylheptyl, neodecyl, lauryl, myristyl, stearyl, iso-stearyl, hydrogenated coco, hydrogenated soya, and hydrogenated tallow.

The first dispersant and the second dispersant may be derivatives of polyether amines or polyether polyamines. Typical polyether amine compounds contain at least one ether unit and will be chain terminated with at least one amine moiety. The polyether polyamines can be based on polymers derived from C2-C6 epoxides such as ethylene oxide, propylene oxide, and butylene oxide. Examples of polyether polyamines are sold under the Jeffamine® brand and are commercially available from Hunstman Corporation.

In one embodiment, the second dispersant is a polyisobutylene succinimide. In another embodiment, the second dispersant is a polyisobutylene succinimide that is mono succinated.

The lubricating compositions of the instant disclosure may include 2 to 20 wt % of a dispersant additive package. In some embodiments, the lubricating composition includes 2 to 15 wt % of the dispersant additive package. In other embodiments, the lubricating composition includes 2 to 10 wt % of the dispersant additive package. In some embodiments, the lubricating composition includes 2 to 8 wt % of the dispersant additive package. In other embodiments, the lubricating composition includes 4 to 8 wt % of the dispersant additive package.

The dispersant additive package may include from 1 to 19 wt % of the acylated poly(1-olefin)-based dispersant (first dispersant) and from 1 to 19 wt % of the polyisobutylene-based dispersant (second dispersant). In another embodiment, the dispersant additive package includes 2 to 8 wt % of the first dispersant and from 1 to 6 wt % of the second dispersant. In one embodiment, the first dispersant is a polydecene succinimide present in the lubricating composition in an amount of from 2 to 8 wt % and the second dispersant is a polyisobutylene succinimide dispersant present in and amount of from 2 to 6 wt %.

The lubricating compositions disclosed herein include a dispersant additive package including the acylated poly(1-olefin)-based dispersant and the polyisobutylene-based dispersant at a weight ratio of acylated poly(1-olefin)-based dispersant to the acylated polyisobutylene-based dispersant of from 3:1 to 1:3. In one embodiment the ratio is 2:1 to 1:2. In another embodiment the ratio is 3:2 to 2:3.

The lubricating composition including the dispersant additive package has a kinematic viscosity at 100° C. of from 5 to 12 cSt (mm²/s) and a kinematic viscosity at 40° C. of from 40 to 50 cSt (mm²/s). In another embodiment, the lubricating composition including the dispersant additive package has a kinematic viscosity at 100° C. of from 6 to 10 cSt (mm²/s) and a kinematic viscosity at 40° C. of from 40 to 47 cSt (mm²/s).

The lubricating composition including the dispersant additive package has a high temperature, high shear viscosity (HTHS) of less than 3 mPa-s measured at 150° C. per ASTM D4683. In one embodiment, the HTHS viscosity is less than 2.6 mPa-s. In another embodiment, the HTHS of the lubricating composition is less than 2.1 mPa-s.

The lubricating composition including the dispersant additive package has a TBN of from 4 to 14 mg KOH/g. In another embodiment, the lubricating TBN is from 5 to 10 or 6 to 8 mg KOH/g.

Formulation Additives:

Lubricating compositions of the instant disclosure, in addition to the dispersant additive package disclosed herein, may further contain one or more additive additives as described below.

Anti-Wear Agent

Anti-wear agents include phosphorus-containing compounds as well as phosphorus free compounds.

Phosphorus-containing anti-wear agents are well known to one skilled in the art and include metal dialkyl(dithio)phosphate salts, hydrocarbyl phosphites, hydrocarbyl phosphines, hydrocarbyl phosphonates, alkylphosphate esters, amine or ammonium (alkyl)phosphate salts, and combinations thereof.

In one embodiment, the phosphorus-containing ant-wear agent may be a metal dialkyldithiophosphate, which may include a zinc dialkyldithiophosphate. Such zinc salts are often referred to as zinc dialkyldithiophosphates (ZDDP) or simply zinc dithiophosphates (ZDP). They are well known and readily available to those skilled in the art of lubricant formulation. Further zinc dialkyldithiophosphates may be described as primary zinc dialkyldithiophosphates or as secondary zinc dialkyldithiophosphates, depending on the structure of the alcohol used in its preparation. In some embodiments the instant compositions may include primary zinc dialkyldithiophosphates. In some embodiments, the compositions include secondary zinc dialkyldithiophosphates. In some embodiments, the compositions include a mixture of primary and secondary zinc dialkyldithiophosphates. In some embodiments component (b) is a mixture of primary and secondary zinc dialkyldithiophosphates where the ratio of primary zinc dialkyldithiophosphates to secondary zinc dialkyldithiophosphates (one a weight basis) is at least 1:1, or even at least 1:1.2, or even at least 1:1.5 or 1:2, or 1:10.

Examples of suitable metal dialkyldithiophosphate include metal salts of the formula:

where R¹ and R² are independently hydrocarbyl groups containing 3 to 24 carbon atoms, or 3 to 12 carbon atoms, or 3 to 8 carbon atoms; M is a metal having a valence n and generally incudes zinc, copper, iron, cobalt, antimony, manganese, and combinations thereof. In one embodiment R¹ and R² are secondary aliphatic hydrocarbyl groups containing 3 to 8 carbon atoms, and M is zinc.

ZDDP may be present in the composition in an amount to deliver 0.01 weight percent to 0.12 weight percent phosphorus to the lubricating composition. ZDDP may be present in an amount to deliver at least 100 ppm, or at least 300 ppm, or at least 500 ppm of phosphorus to the composition up to no more than 1200 ppm, or no more than 1000 ppm, or no more than 800 ppm phosphorus to the composition.

In one embodiment, the phosphorus-containing anti-wear agent may be a zinc free phosphorus compound. The zinc-free phosphorus anti-wear agent may contain sulfur or may be sulfur-free. Sulfur-free phosphorus-containing antiwear agents include hydrocarbyl phosphites, hydrocarbyl phosphines, hydrocarbyl phosphonates, alkylphosphate esters, amine or ammonium phosphate salts, or mixtures thereof.

In one embodiment, the anti-wear agent may be a phosphorus-free compound.

Examples of suitable phosphorus-free antiwear agents include titanium compounds, hydroxy-carboxylic acid derivatives such as esters, amides, imides or amine or ammonium salt, sulfurized olefins, (thio)carbamate-containing compounds, such as (thio)carbamate esters, (thio)carbamate amides, (thio)carbamic ethers, alkylene-coupled (thio)carbamates, and bis(S-alkyl(dithio)carbamyl) disulfides. Suitable hydroxy-carboxylic acid derivatives include tartaric acid derivatives, malic acid derivatives, citric acid derivatives, glycolic acid derivatives, lactic acid derivatives, and mandelic acid derivatives.

The antiwear agent may in one embodiment include a tartrate or tartrimide as disclosed in International Publication WO 2006/044411 or Canadian Patent CA 1 183 125. The tartrate or tartrimide may contain alkyl-ester groups, where the sum of carbon atoms on the alkyl groups is at least 8. The antiwear agent may in one embodiment include a citrate as is disclosed in US Patent Application 20050198894.

The anti-wear agent may be represented by the formula:

wherein Y and Y′ are independently —O—, >NH, >NR³, or an imide group formed by taking together both Y and Y′ groups and forming a R¹—N< group between two >C═O groups; X is independently —Z—O—Z′—, >CH₂, >CHR⁴, >CR⁴R⁵, >C(OH)(CO₂R²), >C(CO₂R²)₂, or >CHOR⁶; Z and Z′ are independently >CH₂, >CHR⁴, >CR⁴R⁵, >C(OH)(CO₂R²), or >CHOR⁶; n is 0 to 10, with the proviso that when n=1, X is not >CH₂, and when n=2, both X's are not >CH₂; m is 0 or 1; R¹ is independently hydrogen or a hydrocarbyl group, typically containing 1 to 150 carbon atoms, with the proviso that when R¹ is hydrogen, m is 0, and n is more than or equal to 1; R² is a hydrocarbyl group, typically containing 1 to 150 carbon atoms; R³, R⁴ and R⁵ are independently hydrocarbyl groups; and R⁶ is hydrogen or a hydrocarbyl group, typically containing 1 to 150 carbon atoms.

The phosphorus-free antiwear agent may be present at 0 wt % to 3 wt %, or 0.1 wt % to 1.5 wt %, or 0.5 wt % to 1.1 wt % of the lubricating composition.

The antiwear agent, be it phosphorus-containing, phosphorus free, or mixtures, may be present at 0.15 weight % to 6 weight %, or 0.2 weight % to 3.0 weight %, or 0.5 weight % to 1.5 weight % of the lubricating composition.

Another class of additives includes oil-soluble titanium compounds as disclosed in U.S. Pat. No. 7,727,943 and US2006/0014651. The oil-soluble titanium compounds may function as antiwear agents, friction modifiers, antioxidants, deposit control additives, or more than one of these functions. In one embodiment the oil soluble titanium compound is a titanium (IV) alkoxide. The titanium alkoxide is formed from a monohydric alcohol, a polyol or mixtures thereof. The monohydric alkoxides may have 2 to 16, or 3 to 10 carbon atoms. In one embodiment, the titanium alkoxide is titanium (IV) isopropoxide. In one embodiment, the titanium alkoxide is titanium (IV) 2-ethylhexoxide. In one embodiment, the titanium compound comprises the alkoxide of a vicinal 1,2-diol or polyol. In one embodiment, the 1,2-vicinal diol comprises a fatty acid mono-ester of glycerol, often the fatty acid is oleic acid.

Ashless Antioxidant

The instant compositions may include an ashless antioxidant. Ashless antioxidants may comprise one or more of arylamines, diarylamines, alkylated arylamines, alkylated diaryl amines, phenols, hindered phenols, sulfurized olefins, or mixtures thereof. In one embodiment the lubricating composition includes an antioxidant, or mixtures thereof. The antioxidant may be present at 1.2 weight % to 7 weight %, or 1.2 weight % to 6 weight %, or 1.5 weight % to 5 weight %, of the lubricating composition.

The diarylamine or alkylated diarylamine may be a phenyl-α-naphthylamine (PANA), an alkylated diphenylamine, or an alkylated phenylnapthylamine, or mixtures thereof. The alkylated diphenylamine may include di-nonylated diphenylamine, nonyl diphenylamine, octyl diphenylamine, di-octylated diphenylamine, di-decylated diphenylamine, decyl diphenylamine and mixtures thereof. In one embodiment, the diphenylamine may include nonyl diphenylamine, dinonyl diphenylamine, octyl diphenylamine, dioctyl diphenylamine, or mixtures thereof. In one embodiment the alkylated diphenylamine may include nonyl diphenylamine, or dinonyl diphenylamine. The alkylated diarylamine may include octyl, di-octyl, nonyl, di-nonyl, decyl or di-decyl phenylnapthylamines.

The diarylamine antioxidant may be present on a weight basis of this lubrication composition at 0.1% to 10/a, 0.35% to 5%, or even 0.5% to 2%.

The phenolic antioxidant may be a simple alkyl phenol, a hindered phenol, or coupled phenolic compounds.

The hindered phenol antioxidant often contains a secondary butyl and/or a tertiary butyl group as a sterically hindering group. The phenol group may be further substituted with a hydrocarbyl group (typically linear or branched alkyl) and/or a bridging group linking to a second aromatic group. Examples of suitable hindered phenol antioxidants include 2,6-di-tert-butylphenol, 4-methyl-2,6-di-tert-butylphenol, 4-ethyl-2,6-di-tert-butylphenol, 4 propyl-2,6-di-tert-butyl,phenol or 4-butyl-2,6-di-tert-butylphenol, 4-dodecyl-2,6-di-tert-butyl,phenol, or butyl 3-(3,5-ditert-butyl-4-hydroxyphenyl)propanoate. In one embodiment, the hindered phenol antioxidant may be an ester and may include, e.g., Irganox™ L-135 from Ciba.

Coupled phenols often contain two alkylphenols coupled with alkylene groups to form bisphenol compounds. Examples of suitable coupled phenol compounds include 4,4′-methylene bis-(2,6-di-tert-butyl phenol), 4-methyl-2,6-di-tert-butylphenol, 2,2′-bis-(6-t-butyl-4-heptylphenol); 4,4′-bis(2,6-di-t-butyl phenol), 2,2′-methylenebis(4-methyl-6-t-butylphenol), and 2,2′-methylene bis(4-ethyl-6-t-butylphenol).

Phenols may include polyhydric aromatic compounds and their derivatives. Examples of suitable polyhydric aromatic compounds include esters and amides of gallic acid, 2,5-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid, 1,4-dihydroxy-2-naphthoic acid, 3,5-dihydroxynaphthoic acid, 3,7-dihydroxy naphthoic acid, and mixtures thereof.

In one embodiment, the phenolic antioxidant comprises a hindered phenol. In another embodiment the hindered phenol is derived from 2,6-ditertbutyl phenol.

In one embodiment the lubricating composition comprises a phenolic antioxidant in a range of 0.01 wt % to 5 wt %, or 0.1 wt % to 4 wt %, or 0.2 wt % to 3 wt %, or 0.5 wt % to 2 wt % of the lubricating composition.

Sulfurized olefins are well known commercial materials, and those which are substantially nitrogen-free, that is, not containing nitrogen functionality, are readily available. The olefinic compounds which may be sulfurized are diverse in nature. They contain at least one olefinic double bond, which is defined as a non-aromatic double bond; that is, one connecting two aliphatic carbon atoms. These materials generally have sulfide linkages having 1 to 10 sulfur atoms, for instance, 1 to 4, or 1 or 2. Suitable sulfurized olefins include sulfurized alpha olefins containing 10 to 22 carbon atoms, sulfurized isobutylene, sulfurized di-isobutylene, 4-Carbobutoxy cyclohexene, and combinations thereof.

Ashless antioxidants may be used separately or in combination. In one embodiment, two or more different antioxidants are used in combination, such that there is at least 0.1 weight percent of each of the at least two antioxidants and wherein the combined amount of the ashless antioxidants is 1.2 to 7 weight percent. In one embodiment, there may be at least 0.25 to 3 weight percent of each ashless antioxidant.

Metal-Containing Detergent

Metal-containing detergents are well known in the art. They are generally made up of metal salts, especially alkali metals and alkaline earth metals, of acidic organic substrates. Metal-containing detergents may be neutral, i.e. a stoichiometric salt of the metal and substrate also referred to as neutral soap or soap, or overbased.

Metal overbased detergents, otherwise referred to as overbased detergents, metal-containing overbased detergents or superbased salts, are characterized by a metal content in excess of that which would be necessary for neutralization according to the stoichiometry of the metal and the particular acidic organic compound, i.e. the substrate, reacted with the metal. The overbased detergent may comprise one or more of non-sulfur containing phenates, sulfur containing phenates, sulfonates, salicylates, and mixtures thereof.

The amount of excess metal is commonly expressed in terms of substrate to metal ratio. The terminology “metal ratio” is used in the prior art and herein to define the ratio of the total chemical equivalents of the metal in the overbased salt to the chemical equivalents of the metal in the salt which would be expected to result from the reaction between the hydrocarbyl substituted organic acid; the hydrocarbyl-substituted phenol or mixtures thereof to be overbased, and the basic metal compound according to the known chemical reactivity and the stoichiometry of the two reactants. Thus, in a normal or neutral salt (i.e. soap) the metal ratio is one and, in an overbased salt, the metal ratio is greater than one, especially greater than 1.3. The overbased metal detergent may have a metal ratio of 5 to 30, or a metal ratio of 7 to 22, or a metal ratio of at least 11.

The metal-containing detergent may also include “hybrid” detergents formed with mixed surfactant systems including phenate and/or sulfonate components, e.g. phenate-salicylates, sulfonate-phenates, sulfonate-salicylates, sulfonates-phenates-salicylates, as described, for example, in U.S. Pat. Nos. 6,429,178; 6,429,179; 6,153,565; and 6,281,179. Where, for example, a hybrid sulfonate/phenate detergent is employed, the hybrid detergent would be considered equivalent to amounts of distinct phenate and sulfonate detergents introducing like amounts of phenate and sulfonate soaps, respectively. Overbased phenates and salicylates typically have a total base number of 180 to 450 TBN. Overbased sulfonates typically have a total base number of 250 to 600, or 300 to 500. Overbased detergents are known in the art.

Alkylphenols are often used as constituents in and/or building blocks for overbased detergents. Alkylphenols may be used to prepare phenate, salicylate, salixarate, or saligenin detergents or mixtures thereof. Suitable alkylphenols may include para-substituted hydrocarbyl phenols. The hydrocarbyl group may be linear or branched aliphatic groups of 1 to 60 carbon atoms, 8 to 40 carbon atoms, 10 to 24 carbon atoms, 12 to 20 carbon atoms, or 16 to 24 carbon atoms. In one embodiment, the alkylphenol overbased detergent is prepared from an alkylphenol or mixture thereof that is free of or substantially free of (i.e. contains less than 0.1 weight percent) p-dodecylphenol. In one embodiment, the lubricating composition contains less than 0.3 weight percent of alkylphenol, less than 0.1 weight percent of alkylphenol, or less than 0.05 weight percent of alkylphenol.

The overbased metal-containing detergent may be alkali metal or alkaline earth metal salts. In one embodiment, the overbased detergent may be sodium salts, calcium salts, magnesium salts, or mixtures thereof of the phenates, sulfur-containing phenates, sulfonates, salixarates and salicylates. In one embodiment, the overbased detergent is a calcium detergent, a magnesium detergent or mixtures thereof. In one embodiment, the overbased calcium detergent may be present in an amount to deliver at least 500 ppm calcium by weight and no more than 3000 ppm calcium by weight, or at least 1000 ppm calcium by weight, or at least 2000 ppm calcium by weight, or no more than 2500 ppm calcium by weight to the lubricating composition. In one embodiment, the overbased detergent may be present in an amount to deliver no more than 500 ppm by weight of magnesium to the lubricating composition, or no more than 330 ppm by weight, or no more than 125 ppm by weight, or no more than 45 ppm by weight. In one embodiment, the lubricating composition is essentially free of (i.e. contains less than 10 ppm) magnesium resulting from the overbased detergent. In one embodiment, the overbased detergent may be present in an amount to deliver at least 200 ppm by weight of magnesium, or at least 450 ppm by weight magnesium, or at least 700 ppm by weight magnesium to the lubricating composition. In one embodiment, both calcium and magnesium containing detergents may be present in the lubricating composition. Calcium and magnesium detergents may be present such that the weight ratio of calcium to magnesium is 10:1 to 1:10, or 8:3 to 4:5, or 1:1 to 1:3. In one embodiment, the overbased detergent is free of or substantially free of sodium.

In one embodiment, the sulfonate detergent may be predominantly a linear alkylbenzene sulfonate detergent having a metal ratio of at least 8 as is described in paragraphs [0026] to [0037] of US Patent Publication 2005/065045 (and granted as U.S. Pat. No. 7,407,919). The linear alkylbenzene sulfonate detergent may be particularly useful for assisting in improving fuel economy. The linear alkyl group may be attached to the benzene ring anywhere along the linear chain of the alkyl group, but often in the 2, 3 or 4 position of the linear chain, and in some instances, predominantly in the 2 position, resulting in the linear alkylbenzene sulfonate detergent.

Salicylate detergents and overbased salicylate detergents may be prepared in at least two different manners. Carbonylation (also referred to as carboxylation) of a p-alkylphenol is described in many references including U.S. Pat. No. 8,399,388. Carbonylation may be followed by overbasing to form overbased salicylate detergent. Suitable p-alkylphenols include those with linear and/or branched hydrocarbyl groups of 1 to 60 carbon atoms. Salicylate detergents may also be prepared by alkylation of salicylic acid, followed by overbasing, as described in U.S. Pat. No. 7,009,072. Salicylate detergents prepared in this manner, may be prepared from linear and/or branched alkylating agents (usually 1-olefins) containing 6 to 50 carbon atoms, 10 to 30 carbon atoms, or 14 to 24 carbon atoms. In one embodiment, the overbased detergent is a salicylate detergent. In one embodiment, the salicylate detergent is free of unreacted p-alkylphenol (i.e. contains less than 0.1 weight percent). In one embodiment, the salicylate detergent is prepared by alkylation of salicylic acid.

The metal-containing overbased detergents may be present at 0.2 wt % to 15 wt %, or 0.3 wt % to 10 wt %, or 0.3 wt % to 8 wt %, or 0.4 wt % to 3 wt %. For example, in a heavy duty diesel engine, the detergent may be present at 2 wt % to 3 wt % of the lubricating composition. For a passenger car engine, the detergent may be present at 0.2 wt % to 1 wt % of the lubricating composition.

Metal-containing detergents contribute sulfated ash to a lubricating composition. Sulfated ash may be determined by ASTM D874. In one embodiment, the lubricating composition comprises a metal-containing detergent in an amount to deliver at least 0.4 weight percent sulfated ash to the total composition. In another embodiment, the metal-containing detergent is present in an amount to deliver at least 0.6 weight percent sulfated ash, or at least 0.75 weight percent sulfated ash, or even at least 0.9 weight percent sulfated ash to the lubricating composition. In one embodiment, the metal-containing overbased detergent is present in an amount to deliver 0.1 weight percent to 0.8 weight percent sulfated ash to the lubricating composition.

In addition to ash and TBN, overbased detergents contribute detergent soap, also referred to as neutral detergent salt, to the lubricating composition. Soap, being a metal salt of the substrate, may act as a surfactant in the lubricating composition. In one embodiment, the lubricating composition comprises 0.05 weight percent to 1.5 weight percent detergent soap, or 0.1 weight percent to 0.9 weight percent detergent soap. In one embodiment, the lubricating composition contains no more than 0.5 weight percent detergent soap. The overbased detergent may have a weight ratio of ash:soap of 5:1 to 1:2.3, or 3.5:1 to 1:2, or 2.9:1 to 1:1:7.

The lubricating compositions may comprise a dispersant different from the dispersants of the invention. The dispersant may be a Mannich dispersant or mixtures thereof.

Polymeric Viscosity Modifier

The lubricating composition may contain a polymeric viscosity modifier, a dispersant viscosity modifier different from that of that invention, or combinations thereof. The dispersant viscosity modifier may be generally understood to be a functionalized, i.e. derivatized, form of a polymer similar to that of the polymeric viscosity modifier.

The polymeric viscosity modifier may be an olefin (co)polymer, a poly(meth)acrylate (PMA), a vinyl aromatic-diene copolymer, or mixtures thereof. In one embodiment, the polymeric viscosity modifier is an olefin (co)polymer.

The olefin polymer may be derived from isobutylene or isoprene. In one embodiment, the olefin polymer is prepared from ethylene and a higher olefin within the range of C3-C10 alpha-mono-olefins, for example, the olefin polymer may be prepared from ethylene and propylene.

In one embodiment, the olefin polymer may be a polymer of 15 to 80 mole percent of ethylene, for example, 30 mol percent to 70 mol percent ethylene and from and from 20 to 85 mole percent of C3 to C10 mono-olefins, such as propylene, for example, 30 to 70 mol percent propylene or higher mono-olefins. Terpolymer variations of the olefin copolymer may also be used and may contain up to 15 mol percent of a non-conjugated diene or triene. Non-conjugated dienes or trienes may have 5 to about 14 carbon atoms. The non-conjugated diene or triene monomers may be characterized by the presence of a vinyl group in the structure and can include cyclic and bicycle compounds. Representative dienes include 1,4-hexadiene, 1,4-cyclohexadiene, dicyclopentadiene, 5-ethyldiene-2-norbornene, 5-methylene-2-norbornene, 1,5-heptadiene, and 1,6-octadiene.

In one embodiment, the olefin copolymer may be a copolymer of ethylene, propylene, and butylene. The polymer may be prepared by polymerizing a mixture of monomers comprising ethylene, propylene and butylene. These polymers may be referred to as copolymers or terpolymers. The terpolymer may comprise from about 5 mol % to about 20 mol %, or from about 5 mol % to about 10 mol % structural units derived from ethylene; from about 60 mol % to about 90 mol %, or from about 60 mol % to about 75 mol structural units derived from propylene; and from about 5 mol % to about 30 mol %, or from about 15 mol % to about 30 mol % structural units derived from butylene. The butylene may comprise any isomers or mixtures thereof, such as n-butylene, iso-butylene, or a mixture thereof. The butylene may comprise butene-1. Commercial sources of butylene may comprise butene-1 as well as butene-2 and butadiene. The butylene may comprise a mixture of butene-1 and isobutylene wherein the weight ratio of butene-1 to isobutylene is about 1:0.1 or less. The butylene may comprise butene-1 and be free of or essentially free of isobutylene.

In one embodiment, the olefin copolymer may be a copolymer of ethylene and butylene. The polymer may be prepared by polymerizing a mixture of monomers comprising ethylene and butylene wherein, the monomer composition is free of or substantially free of propylene monomers (i.e. contains less than 1 weight percent of intentionally added monomer). The copolymer may comprise 30 to 50 mol percent structural units derived from butylene; and from about 50 mol percent to 70 mol percent structural units derived from ethylene. The butylene may comprise a mixture of butene-1 and isobutylene wherein the weight ratio of butene-1 to isobutylene is about 1:0.1 or less. The butylene may comprise butene-1 and be free of or essentially free of isobutylene.

Useful olefin polymers, in particular, ethylene-α-olefin copolymers have a number average molecular weight ranging from 4500 to 500,000, for example, 5000 to 100,000, or 7500 to 60,000, or 8000 to 45,000.

The formation of functionalized ethylene-α-olefin copolymer is well known in the art, for instance those described in U.S. Pat. No. 7,790,661 column 2, line 48 to column 10, line 38. Additional detailed descriptions of similar functionalized ethylene-α-olefin copolymers are found in International Publication WO2006/015130 or U.S. Pat. Nos. 4,863,623; 6,107,257; 6,107,258; 6,117,825; and 7,790,661. In one embodiment the functionalized ethylene-α-olefin copolymer may include those described in U.S. Pat. No. 4,863,623 (see column 2, line 15 to column 3, line 52) or in International Publication WO2006/015130 (see page 2, paragraph [0008] and preparative examples are described paragraphs [0065] to [0073]).

In one embodiment, the lubricating composition comprises a dispersant viscosity modifier (DVM). The DVM may comprise an olefin polymer that has been modified by the addition of a polar moiety.

The olefin polymers are functionalized by modifying the polymer by the addition of a polar moiety. In one useful embodiment, the functionalized copolymer is the reaction product of an olefin polymer grafted with an acylating agent. In one embodiment, the acylating agent may be an ethylenically unsaturated acylating agent. Useful acylating agents are typically α, β unsaturated compounds having at least one ethylenic bond (prior to reaction) and at least one, for example two, carboxylic acid (or its anhydride) groups or a polar group which is convertible into said carboxyl groups by oxidation or hydrolysis. The acylating agent grafts onto the olefin polymer to give two carboxylic acid functionalities. Examples of useful acylating agents include maleic anhydride, chlormaleic anhydride, itaconic anhydride, or the reactive equivalents thereof, for example, the corresponding dicarboxylic acids, such as maleic acid, fumaric acid, cinnamic acid, (meth)acrylic acid, the esters of these compounds and the acid chlorides of these compounds.

In one embodiment, the functionalized ethylene-α-olefin copolymer comprises an olefin copolymer grafted with the acyl group which is further functionalized with a hydrocarbyl amine, a hydrocarbyl alcohol group, amino- or hydroxy-terminated polyether compounds, and mixtures thereof.

Amine functional groups may be added to the olefin polymer by reacting the olefin copolymer (typically, an ethylene-α-olefin copolymer, such as an ethylene-propylene copolymer) with an acylating agent (typically maleic anhydride) and a hydrocarbyl amine having a primary or secondary amino group. In one embodiment, the hydrocarbyl amine may be selected from aromatic amines, aliphatic amines, and mixtures thereof.

In one embodiment, the hydrocarbyl amine component may comprise at least one aromatic amine containing at least one amino group capable of condensing with said acyl group to provide a pendant group and at least one additional group comprising at least one nitrogen, oxygen, or sulfur atom, wherein said aromatic amine is selected from the group consisting of (i) a nitro-substituted aniline, (ii) an amine comprising two aromatic moieties linked by a C(O)NR— group, a —C(O)O— group, an —O— group, an N═N— group, or an —SO₂— group where R is hydrogen or hydrocarbyl, one of said aromatic moieties bearing said condensable amino group, (iii) an aminoquinoline, (iv) an aminobenzimidazole, (v) an N,N-dialkylphenylenediamine, (vi), an aminodiphenylamine (also N-phenyl-phenylenediamine), and (vii) a ring-substituted benzylamine.

In another one embodiment, the polar moiety added to the functionalized ethylene-α-olefin copolymer may be derived from a hydrocarbyl alcohol group, containing at least one hydroxy group capable of condensing with said acyl group to provide a pendant group and at least one additional group comprising at least one nitrogen, oxygen, or sulfur atom. The alcohol functional groups may be added to the olefin polymer by reacting the olefin copolymer with an acylating agent (typically maleic anhydride) and a hydrocarbyl alcohol. The hydrocarbyl alcohol may be a polyol compound. Suitable hydrocarbyl polyols include ethylene glycol and propylene glycol, trimethylol propane (TMP), pentaerythritol, and mixtures thereof.

In another one embodiment, the polar moiety added to the functionalized ethylene-α-olefin copolymer may be amine-terminated polyether compounds, hydroxy-terminated polyether compounds, and mixtures thereof. The hydroxy terminated or amine terminated polyether may be selected from the group comprising polyethylene glycols, polypropylene glycols, mixtures of one or more amine terminated polyether compounds containing units derived from ethylene oxides, propylene oxides, butylene oxides or some combination thereof, or some combination thereof. Suitable polyether compounds include Synalox® line of polyalkylene glycol compounds, the UCON™ OSP line of polyether compounds available from Dow Chemical, Jeffamine® line of polyether amines available from Huntsman.

In one embodiment, lubricating composition may comprise a poly(meth)acrylate polymeric viscosity modifier. As used herein, the term “(meth)acrylate” and its cognates means either methacrylate or acrylate, as will be readily understood.

In one embodiment, the poly(meth)acrylate polymer is prepared from a monomer mixture comprising (meth)acrylate monomers having alkyl groups of varying length. The (meth)acrylate monomers may contain alkyl groups that are straight chain or branched chain groups. The alkyl groups may contain 1 to 24 carbon atoms, for example 1 to 20 carbon atoms.

The poly(meth)acrylate polymers described herein are formed from monomers derived from saturated alcohols, such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-methylpentyl (meth)acrylate, 2-propylheptyl (meth)acrylate, 2-butyloctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, nonyl (meth)acrylate, isooctyl (meth)acrylate, isononyl (meth)acrylate, 2-tert-butylheptyl (meth)acrylate, 3-isopropylheptyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, 5-methylundecyl (meth)acrylate, dodecyl (meth)acrylate, 2-methyldodecyl (meth)acrylate, tridecyl (meth)acrylate, 5-methyltridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, 2-methylhexadecyl (meth)acrylate, heptadecyl (meth)acrylate, 5-isopropylheptadecyl (meth)acrylate, 4-tert-butyloctadecyl (meth)acrylate, 5-ethyloctadecyl (meth)acrylate, 3-isopropyl-octadecyl-(meth)acrylate, octadecyl (meth)acrylate, nonadecyl (meth)acrylate, eicosyl (meth)acrylate, (meth)acrylates derived from unsaturated alcohols, such as oleyl (meth)acrylate; and cycloalkyl (meth)acrylates, such as 3-vinyl-2-butylcyclohexyl (meth)acrylate or bornyl (meth)acrylate.

Other examples of monomers include alkyl (meth)acrylates with long-chain alcohol-derived groups which may be obtained, for example, by reaction of a (meth)acrylic acid (by direct esterification) or methyl (meth)acrylate (by transesterification) with long-chain fatty alcohols, in which reaction a mixture of esters such as (meth)acrylate with alcohol groups of various chain lengths is generally obtained. These fatty alcohols include Oxo Alcohol®7911, Oxo Alcohol® 7900 and Oxo Alcohol® 1100 of Monsanto; Alphanol® 79 of ICI; Nafol® 1620, Alfol® 610 and Alfol® 810 of Condea (now Sasol); Epal® 610 and Epal® 810 of Ethyl Corporation; Linevol® 79, Linevol® 911 and Dobanol® 25 L of Shell AG; Lial®125 of Condea Augusta, Milan; Dehydad® and Lorol® of Henkel KGaA (now Cognis) as well as Linopol® 7-11 and Acropol® 91 of Ugine Kuhlmann.

In one embodiment, the poly(meth)acrylate polymer comprises a dispersant monomer; dispersant monomers include those monomers which may copolymerize with (meth)acrylate monomers and contain one or more heteroatoms in addition to the carbonyl group of the (meth)acrylate. The dispersant monomer may contain a nitrogen-containing group, an oxygen-containing group, or mixtures thereof.

The oxygen-containing compound may include hydroxyalkyl(meth)acrylates such as 3-hydroxypropyl(meth)acrylate, 4-dihydroxybutyl(meth)acrylate, 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate, 2,5-dimethyl-1,6-hexanediol (meth)acrylate, 1,10-decanediol(meth)acrylate, carbonyl-containing (meth)acrylates such as 2-carboxyethyl(meth)acrylate, carboxymethyl(meth)acrylate, oxazolidinylethyl(meth)acrylate, N-(methacryloyloxy)formamide, acetonyl(meth)acrylate, N-methacryloylmorpholine, N-methacryloyl-2-pyrrolidinone, N-(2-methacryloyl-oxyethyl)-2-pyrrolidinone, N-(3-methacryloyloxypropyl)-2-pyrrolidinone, N-(2-methacryloyloxypentadecyl)-2-pyrrolidinone, N-(3-methacryloyloxy-heptadecyl)-2-pyrrolidinone; glycol di(meth)acrylates such as 1,4-butanediol(meth)acrylate, 2-butoxyethyl(meth)acrylate, 2-ethoxyethoxymethyl(meth)acrylate, 2-ethoxyethyl(meth)acrylate, or mixtures thereof.

The nitrogen-containing compound may be a (meth)acrylamide or a nitrogen containing (meth)acrylate monomer. Examples of a suitable nitrogen-containing compound include N,N-dimethylacrylamide, N-vinyl carbonamides such as N-vinyl-formamide, vinyl pyridine, N-vinylacetoamide, N-vinyl propionamides, N-vinyl hydroxy-acetoamide, N-vinyl imidazole, N-vinyl pyrrolidinone, N-vinyl caprolactam, dimethylaminoethyl acrylate (DMAEA), dimethylaminoethyl methacrylate (DMAEMA), dimethylaminobutyl acrylamide, dimethylaminopropyl methacrylate (DMAPMA), dimethylaminopropyl acrylamide, dimethyl-aminopropyl methacrylamide, dimethylaminoethyl acrylamide or mixtures thereof.

Dispersant monomers may be present in an amount up to 5 mol percent of the monomer composition of the (meth)acrylate polymer. In one embodiment, the poly(meth)acrylate is present in an amount 0 to 5 mol percent, 0.5 to 4 mol percent, or 0.8 to 3 mol percent of the polymer composition. In one embodiment, the poly(meth)acrylate is free of or substantially free of dispersant monomers.

In one embodiment, the poly(meth)acrylate comprises a block copolymer or tapered block copolymer. Block copolymers are formed from a monomer mixture comprising one or more (meth)acrylate monomers, wherein, for example, a first (meth)acrylate monomer forms a discrete block of the polymer joined to a second discrete block of the polymer formed from a second (meth)acrylate monomer. While block copolymers have substantially discrete blocks formed from the monomers in the monomer mixture, a tapered block copolymer may be composed of, at one end, a relatively pure first monomer and, at the other end, a relatively pure second monomer. The middle of the tapered block copolymer is more of a gradient composition of the two monomers.

In one embodiment, the poly(meth)acrylate polymer (P) is a block or tapered block copolymer that comprises at least one polymer block (B₁) that is insoluble or substantially insoluble in the base oil and a second polymer block (B₂) that is soluble or substantially soluble in the base oil.

In one embodiment, the poly(meth)acrylate polymers may have an architecture selected from linear, branched, hyper-branched, cross-linked, star (also referred to as “radial”), or combinations thereof. Star or radial refers to multi-armed polymers. Such polymers include (meth)acrylate-containing polymers comprising 3 or more arms or branches, which, in some embodiments, contain at least about 20, or at least 50 or 100 or 200 or 350 or 500 or 1000 carbon atoms. The arms are generally attached to a multivalent organic moiety which acts as a “core” or “coupling agent.” The multi-armed polymer may be referred to as a radial or star polymer, or even a “comb” polymer, or a polymer otherwise having multiple arms or branches as described herein.

Linear poly(meth)acrylates, random, block or otherwise, may have weight average molecular weight (M_(w)) of 1000 to 400,000 Daltons, 1000 to 150,000 Daltons, or 15,000 to 100,000 Daltons. In one embodiment, the poly(meth)acrylate may be a linear block copolymer with a Mw of 5,000 to 40,000 Daltons, or 10,000 to 30,000 Daltons.

Radial, cross-linked or star copolymers may be derived from linear random or di-block copolymers with molecular weights as described above. A star polymer may have a weight average molecular weight of 10,000 to 1,500,000 Daltons, or 40,000 to 1,000,000 Daltons, or 300,000 to 850,000 Daltons.

In one embodiment, the lubricating composition may comprise a vinylaromatic-diene copolymer. The vinylaromatic-diene copolymer may be a linear or radial block copolymer. In one embodiment the vinylaromatic-diene copolymer may be a hydrogenated styrene-(conjugated diene) block copolymer.

The block copolymer in different embodiments may be a hydrogenated styrene-butadiene copolymer or a hydrogenated styrene-isoprene copolymer. Both block copolymers are known in the art and are disclosed for example in EP 2 001 983 A (Price et al.) for hydrogenated styrene-butadiene and U.S. Pat. No. 5,490,945 (Smith et al.) for hydrogenated styrene-isoprene.

The butadiene block of the hydrogenated styrene-butadiene copolymer may be prepared with by either 1,2-addition or 1,4-addition, with 1,2-addition preferred as is disclosed in EP 2 001 983 A. Using 1,2-addition results in a butadiene block having 20 mol % to 80 mol %, or 25 mol % to 75 mol %, or 30 mol % to 70 mol %, or 40 mol % to 65 mol % of repeat units of branched alkyl groups due to initially-formed pendant unsaturated or vinyl groups, upon hydrogenation, become alkyl branches.

The lubricating compositions may comprise 0.05 weight % to 2 weight %, or 0.08 weight % to 1.8 weight %, or 0.1 to 1.2 weight % of the one or more polymeric viscosity modifiers and/or dispersant viscosity modifiers as described herein.

Other Performance Additives:

Various embodiments of the compositions disclosed herein may optionally comprise one or more additional performance additives. These additional performance additives may include one or more metal deactivators, friction modifiers, corrosion inhibitors, extreme pressure agents, foam inhibitors, demulsifiers, pour point depressants, seal swelling agents, and any combination or mixture thereof. Typically, fully-formulated lubricating oil will contain one or more of these performance additives, and often a package of multiple performance additives. However, such performance additives are included based on the application of the lubricating composition, and the specific performance additive and treat rate thereof would be apparent to one of ordinary skill in the art in view of this disclosure.

In one embodiment, a lubricating composition further comprises a friction modifier. Examples of friction modifiers include long chain fatty acid derivatives of amines, fatty esters, or epoxides; fatty imidazolines such as condensation products of carboxylic acids and polyalkylene-polyamines; amine salts of alkylphosphoric acids; fatty alkyl tartrates; fatty alkyl tartrimides; or fatty alkyl tartramides. The term fatty, as used herein, can mean having a C8-22 linear alkyl group.

Friction modifiers may also encompass materials such as sulfurized fatty compounds and olefins, molybdenum dialkyldithiophosphates, molybdenum dithiocarbamates, sunflower oil or monoester of a polyol and an aliphatic carboxylic acid.

In one embodiment the friction modifier may be selected from the group consisting of long chain fatty acid derivatives of amines, long chain fatty esters, or long chain fatty epoxides; fatty imidazolines; amine salts of alkylphosphoric acids; fatty alkyl tartrates; fatty alkyl tartrimides; and fatty alkyl tartramides. The friction modifier may be present at 0 wt % to 6 wt %, or 0.05 wt % to 4 wt %, or 0.1 wt % to 2 wt % of the lubricating composition.

In one embodiment, the friction modifier may be a long chain fatty acid ester. In another embodiment the long chain fatty acid ester may be a mono-ester or a diester or a mixture thereof, and in another embodiment, the long chain fatty acid ester may be a triglyceride.

In one embodiment, a lubricating composition may further comprise a molybdenum compound. The molybdenum compound may be selected from the group consisting of molybdenum dialkyldithiophosphates, molybdenum dithiocarbamates, amine salts of molybdenum compounds, and mixtures thereof. The molybdenum compound may provide the lubricating composition with 0 to 1000 ppm, or 5 to 1000 ppm, or 10 to 750 ppm, or 5 ppm to 300 ppm, or 20 ppm to 250 ppm of molybdenum

Other performance additives such as corrosion inhibitors include those described in paragraphs 5 to 8 of US Application U.S. Ser. No. 05/038,319, published as WO2006/047486, octyl octanamide, condensation products of dodecenyl succinic acid or anhydride and a fatty acid such as oleic acid with a polyamine. In one embodiment, the corrosion inhibitors include the Synalox® (a registered trademark of The Dow Chemical Company) corrosion inhibitor. The Synalox® corrosion inhibitor may be a homopolymer or copolymer of propylene oxide. The Synalox® corrosion inhibitor is described in more detail in a product brochure with Form No. 118-01453-0702 AMS, published by The Dow Chemical Company. The product brochure is entitled “SYNALOX Lubricants, High-Performance Polyglycols for Demanding Applications.”

The lubricating composition may further include metal deactivators, including derivatives of benzotriazoles (typically tolyltriazole), dimercaptothiadiazole derivatives, 1,2,4-triazoles, benzimidazoles, 2-alkyldithiobenzimidazoles, or2-alkyldithiobenzothiazoles; foam inhibitors, including copolymers of ethyl acrylate and 2-ethylhexylacrylate and copolymers of ethyl acrylate and 2-ethylhexylacrylate and vinyl acetate; demulsifiers including trialkyl phosphates, polyethylene glycols, polyethylene oxides, polypropylene oxides and (ethylene oxide-propylene oxide) polymers; and pour point depressants, including esters of maleic anhydride-styrene, polymethacrylates, polyacrylates or polyacrylamides.

Pour point depressants that may be useful in the lubricating compositions disclosed herein further include polyalphaolefins, esters of maleic anhydride-styrene, poly(meth)acrylates, polyacrylates or polyacrylamides.

In different embodiments, the lubricating composition may have a composition as described in the following table:

Embodiments (weight %) Additive A B C D Acylated poly(1- 0.3 to 1 0.9 to 1.5 to 3 1.9 to 3.8 olefin)-based 2.5 dispersant PIB succinimide 0.1 to 3 0.3 to 0.5 to 9 1.3 to 3.1 Dispersant 7.5 Zinc 0.1 to 1.5 0 to 0.5 0 to 0.1 0.5 to 1.1 dialkyldithiophosphates Metal Sulfonate 0.2 to 4 0.5 to 2 0.8 to 1.5 0.8 to 1.2 Detergents Metal phenate 0 to 1 0.1 to 0.8 0.15 0.5 to 0.9 detergents to 0.5 Other Antiwear Agents 0 to 4 0.1 to 2 0.5 to 1.5 0 to 1.0 Ashless Antioxidants 0.5 to 6 1.2 to 5 2 to 4 1.3 to 2.1 Viscosity Modifier 0 or 0.1 0.5 to 4 0.8 to 2.5 0.6 to 1.1 to 4.5 Friction Modifier 0 or 0.05 0.05 0.1 to 2 0 or 0.05 to 4 to 3 to 1.0 Any Other Performance 0 or 0.05 0 or 0 or 0.05 Additive to 10 0.05 to 8 0.05 to 6 to 1.0 Oil of Lubricating Balance to 100% Viscosity

In one embodiment the lubricating composition may be characterized as having (i) PP4T a sulfur content of 0.5 wt % or less, (ii) a phosphorus content of 0.15 wt % or less, and (iii) a sulfated ash content of 0.5 wt % to 1.5 wt % or less. The lubricating composition may be characterized as having at least one of (i) a sulfur content of 0.2 wt % to 0.4 wt % or less, (ii) a phosphorus content of 0.08 wt % to 0.15 wt %, and (iii) a sulfated ash content of 0.5 wt % to 1.5 wt % or less.

As described above, the invention provides for a method of lubricating an internal combustion engine comprising supplying to the internal combustion engine a lubricating composition as disclosed herein. Generally, the lubricant is added to the lubricating system of the internal combustion engine, which then delivers the lubricating composition to the critical parts of the engine, during its operation, that require lubrication.

The lubricating compositions described above may be utilized in an internal combustion engine. The engine components may have a surface of steel or aluminum (typically a surface of steel) and may also be coated for example with a diamondlike carbon (DLC) coating.

The internal combustion engine may be fitted with an emission control system or a turbocharger. Examples of the emission control system include diesel particulate filters (DPF), gasoline particulate filters (GPF), systems employing selective catalytic reduction (SCR), and combinations thereof.

The internal combustion engine may be a spark-ignited engine (i.e. gasoline) or a compression-ignition (i.e. diesel) engine. Internal combustion engines may be port fuel injected (PFI) or direct injected. In one embodiment, the internal combustion engine is a gasoline direct injection engine (GDI). Direct injection engines are characterized by injection of the fuel, e.g., gasoline, directly into the cylinder. This is distinct from port fuel injection (PFI) and can result in higher efficiency, higher compression, and/or higher brake mean effective pressure than analogous PFI engines.

In one embodiment, the internal combustion engine is equipped with a turbocharger, a supercharger, or combinations thereof. Turbochargers and superchargers both work to increase the volumetric efficiency of engines, i.e. the volume of air that fills a cylinder relative to the volume of the cylinder. Turbochargers and superchargers work by forcing more air into the cylinder, resulting in higher torque for a given displacement, and hence higher BMEP. In addition to improving the efficiency of an engine, turbochargers and superchargers can increase the likelihood of stochastic pre-ignition, especially at lower speeds.

The lubricating compositions disclosed herein may be used in a turbo-charged direct-injection (TDi) engine.

The instant disclosure further relates to methods for lubricating an internal combustion engine with a lubricating composition disclosed herein. The methods of the instant disclosure include supplying to the internal combustion engine, such as a TDi engine, a lubricating composition including an oil of lubricating viscosity and from 2 to 20 wt % of a dispersant additive package, the dispersant additive package including an acylated poly(1-olefin)-based dispersant, where the poly(1-olefin) is comprised of at least 75 mole percent of a C6 to C18 hydrocarbyl and a polyisobutylene succinimide dispersant, where the ratio of the acylated poly(1-olefin)-based dispersant to the polyisobutylene succinimide dispersant is from 3:1 to 1:3, or 2:1 to 1:2, or 3:2 to 2:3. Various embodiments for the lubricating composition suitable for use in the instant methods are disclosed herein.

As used herein, the term “hydrocarbyl substituent” or “hydrocarbyl group” is used in its ordinary sense, which is well-known to those skilled in the art. Specifically, it refers to a group having a carbon atom directly attached to the remainder of the molecule and having predominantly hydrocarbon character including one or more double bonds. Examples of hydrocarbyl groups include: hydrocarbon substituents, that is, aliphatic (e.g., alkyl or alkenyl), alicyclic (e.g., cycloalkyl, cycloalkenyl) substituents, and aromatic-, aliphatic-, and alicyclic-substituted aromatic substituents, as well as cyclic substituents wherein the ring is completed through another portion of the molecule (e.g., two substituents together form a ring); [0081] substituted hydrocarbon substituents, that is, substituents containing non-hydrocarbon groups which, in the context of this invention, do not alter the predominantly hydrocarbon nature of the substituent (e.g., halo (especially chloro and fluoro), hydroxy, alkoxy, mercapto, alkylmercapto, nitro, nitroso, and sulfoxy); hetero substituents, that is, substituents which, while having a predominantly hydrocarbon character, in the context of this invention, contain other than carbon in a ring or chain otherwise composed of carbon atoms and encompass substituents as pyridyl, furyl, thienyl and imidazolyl. Heteroatoms include sulfur, oxygen, and nitrogen. In general, no more than two, or no more than one, non-hydrocarbon substituent will be present for every ten carbon atoms in the hydrocarbyl group; alternatively, there may be no non-hydrocarbon substituents in the hydrocarbyl group.

The present disclosure is not to be limited in terms of the particular embodiments described in this application, which are intended as illustrations of various aspects. Many modifications and variations can be made without departing from its spirit and scope, as will be apparent to those skilled in the art. Functionally equivalent methods and components within the scope of the disclosure, in addition to those enumerated herein, will be apparent to those skilled in the art from the foregoing descriptions. Such modifications and variations are intended to fall within the scope of the appended claims. The present disclosure is to be limited only by the terms of the appended claims, along with the full scope of equivalents to which such claims are entitled. It is to be understood that this disclosure is not limited to particular methods, reagents, compounds, or compositions, which can, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

As used in this document, the singular forms “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise. Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art. Nothing in this disclosure is to be construed as an admission that the embodiments described in this disclosure are not entitled to antedate such disclosure by virtue of prior invention. As used in this document, the term “comprising” means “including, but not limited to.”

While various compositions, methods, and devices are described in terms of “comprising” various components or steps (interpreted as meaning “including, but not limited to”), the compositions, methods, and devices can also “consist essentially of” or “consist of” the various components and steps, and such terminology should be interpreted as defining essentially closed-member groups.

With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.

It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation, no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to embodiments containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.” is used, in general, such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to “at least one of A, B, or C, etc.” is used, in general, such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B.”

In addition, where features or aspects of the disclosure may be described in terms of Markush groups, those skilled in the art will recognize that the disclosure is also thereby described in terms of any individual member or subgroup of members of the Markush group.

As will be understood by one skilled in the art, for any and all purposes, such as in terms of providing a written description, all ranges disclosed herein also encompass any and all possible subranges and combinations of subranges thereof. Any listed range can be easily recognized as sufficiently describing and enabling the same range being broken down into at least equal halves, thirds, quarters, fifths, tenths, etc. As a non-limiting example, each range discussed herein can be readily broken down into a lower third, middle third and upper third, etc. As will also be understood by one skilled in the art all language such as “up to,” “at least,” and the like include the number recited and refer to ranges which can be subsequently broken down into subranges as discussed above. Finally, as will be understood by one skilled in the art, a range includes each individual member. Thus, for example, a group having 1-3 wt. % refers to groups having 1, 2, or 3 wt. %. Similarly, a group having 1-5 wt. % refers to groups having 1, 2, 3, 4, or 5 wt. %, and so forth, including all points therebetween.

As used herein, the term “about” means that a value of a given quantity is within ±20% of the stated value. In other embodiments, the value is within ±15% of the stated value. In other embodiments, the value is within ±10% of the stated value. In other embodiments, the value is within ±5% of the stated value. In other embodiments, the value is within 2.5% of the stated value. In other embodiments, the value is within ±1% of the stated value.

Unless otherwise stated, “wt %” as used herein shall refer to the weight percent based on the total weight of the composition.

The instant disclosure is suitable for lubricant formulations exhibiting improved piston cleanliness ratings over lubricant formulations having only one of the two dispersants of the dispersant additive package, which may be better understood with reference to the following examples:

EXAMPLES

The invention will be further illustrated by the following examples, which set forth particularly advantageous embodiments. While the examples are provided to illustrate the invention, they are not intended to limit it.

A series of poly(1-olefin)-based dispersants, according to aspects of the invention may be prepared as described in the examples provided below.

Example A: Poly(1-decene) Succinc Anhydride (PDSA)

To a 12 L four-necked flask equipped with a thermocouple, overhead stirrer, subsurface gas inlet, syringe line input, heated addition funnel, and air condenser is charged polydecene (Mn=2574)(7500 g). The polymer is heated to 160° C. under positive N2 pressure. Maleic anhydride (377 g) is charged to the heated addition funnel (to maintain it in liquid phase, and t-butylperoxide (149 g) is charged to the syringe; both the maleic anhydride and peroxide are added simultaneously over 2 hours. The reaction mixture is stirred for an additional hour at 160° C. The product mixture is raised to 190° C. and purged with nitrogen (4 SCFH) to remove unreacted maleic anhydride. The product mixture is cooled to ambient temperature and collected without further purification as a dark orange liquid.

Example Polydecene Dispersant 1 (PD1): Preparation of Polydecene Dispersant

To a 12 L four-necked flask equipped with a thermocouple, overhead stirrer, gas inlet tube, Dean-Stark trap, and Friedrichs condenser is charged the PDSA (Example A above) (400 g) and Group II base oil (1745 g). The mixture is heated to 110° C. under N2 purge and triethylene tetraamine (TETA) (95.4 g) is added dropwise over 30 minutes. The reaction mixture is heated to 155° C. while stirring and held at temperature for 5 hours. The product mixture is cooled to 120° C., filtered through a filter-aid medium, cooled to ambient temperature and collected without further purification. The product is a clear orange liquid.

Lubricating Compositions

A series of 0W-20 engine lubricants in Group III and polyalphaolefin (PAO) base oils of lubricating viscosity are prepared containing the dispersant additives described above as well as conventional additives including polymeric viscosity modifier, overbased detergents, antioxidants (combination of phenolic ester and diarylamine), zinc dialkyldithiophosphate (ZDDP), as well as other performance additives as follows (Table 1). The calcium, magnesium, phosphorus, zinc and ash contents of each of the examples are also presented in the table in part to show that each example has a similar amount of these materials and so provide a proper comparison between the comparative and invention examples.

TABLE 1 Engine Oil Lubricating Compositions¹ EX1 EX2 EX3 EX4 EX5 EX6 4 cSt Group III Base Oil Balance to 100% 6 cSt Group III Base Oil 0 15 26.3 0 26.3 27.9 PAO-4 Base Oil 21.6 21.6 21.6 19.6 21.6 21.6 Dispersants Conventional PIBsuccinimide² 5 1.5 2.45 Mono PIBsuccinimide³ 4.9 PD1 (active treat rate) 4.9 9.8 3.4 2.45 Overbased Calcium sulfonate⁴ 1.0 1.0 1.0 1.0 1.0 1.0 Calcium Sulfurized-Phenate⁵ 0.74 0.74 0.74 0.74 0.74 0.74 C3/C6 Secondary ZDDP 0.8 0.8 0.8 0.8 0.8 0.8 Ashless Antioxidant⁶ 1.8 1.8 1.8 1.8 1.8 1.8 Other Additives⁷ 0.31 0.31 0.31 0.31 0.31 0.31 Styrene-diene VI improver 0.76 0.90 0.76 0.76 0.76 0.76 Kinematic Viscosity (100° C.) 8.4 8.3 8.0 8.4 8.5 8.1 High Tempemture High Shear 2.77 2.64 2.59 2.71 2.68 2.63 Viscosity (cP) CCS −35° C. 5570 5900 5440 5190 6140 6200 CALCIUM (ppm) 0.332 0.337 0.315 0.314 0.331 0.339 PHOSPHORUS (ppm) 0.094 0.091 0.092 0.092 0.095 0.095 ZINC (PPM) 0.106 0.099 0.104 0.104 0.108 0.107 ¹All treat rates are oil free, unless otherwise indicated ²Polyisobutylene succinimide derived from 1500 Mn PIB, midsuccan, thermal ene dispersant, functionalized with TETA (TBN 17 mg KOH/g) ³Polyisobutylene succinimide serived from 1000 Mn PIB, mono-succan, functionalized with N,N-(diisostearyl)aminopropylamine (TBN 38 mg KOH/g) ⁴Overbased calcium alkylbenzene sulfonate detergent (TBN 500 mg KOH/g; metal ratio 10) ⁵Overbased calcium sulfur-coupled phenate detergent (TBN400 mg KOH/g) ⁶Combination of alkylated diarylamine compounds and hindered phenol ester compounds ⁷Other additives include pourpoint depressant, friction modifier, and anti-foam agent

Evaluation of Lubricating Compositions

Engine lubricating compositions are evaluated in bench and engine tests designed to evaluate the ability of the lubricant, and thus the detergent, to prevent deposit formation, provide cleanliness, reduce or prevent acid-mediated wear or degradation of the lubricant, and provide sludge handling.

The lubricant examples are subjected to the engine test VW TDI CEC L-78-99 test, also known as the PV1452 test (Table 2). The test is regarded as an industry standard and is a severe assessment of a lubricant's performance capabilities. The test employs a 4-cylinder, 1.9 liter, 81 kW passenger car diesel engine, which is a direct injection engine in which a turbocharger system is used to increase the power output of the unit. The industry test procedure consists of a repeating cycle of hot and cold running conditions. This involves a 30 minute idle period at zero load followed by 180 minutes at full load and 4150 rpm. In the standard test, the entire cycle is then repeated for a total of 54 hours. In this 54 hour period the initial oil fill of 4.5 liters of test lubricant is not topped up.

The pistons are rated against what is known as the DIN rating system. The three piston-ring grooves and the two piston lands that lie between the grooves are rated on a merit scale for deposits and given a score out of 100 by a method known to those skilled in the art. In summary, the higher the number the better the performance: 100 indicates totally clean and 0 indicates totally covered with deposit. The five scores are then averaged to give the overall piston cleanliness merit rating. The scores for each of the four pistons are then averaged to afford the overall piston cleanliness for the test.

The presence of stuck rings is also noted. Any stuck rings results in an automatic failing test.

TABLE 2 Deposit Engine Testing EX1 EX2 EX3 EX4 EX5 EX6 Piston Rating Average 58 58 54 52 60 57 Ring Sticking Average 0 0 0.625 1.25 0 0 No. of Stuck Rings 0 0 2 2 0 0 Maximum Ring Stick 0 0 5 5 0 0

The data indicates that the lubricating compositions containing the combination of both the poly(1-olefin) dispersant and the PIB succinimide dispersant provide improved (or equivalent) deposit control at reduced viscosity.

The amount of each chemical component described is presented exclusive of any solvent or diluent oil, which may be customarily present in the commercial material, that is, on an active chemical basis, unless otherwise indicated. However, unless otherwise indicated, each chemical or composition referred to herein should be interpreted as being a commercial grade material which may contain the isomers, by-products, derivatives, and other such materials which are normally understood to be present in the commercial grade.

It is known that some of the materials described above may interact in the final formulation, so that the components of the final formulation may be different from those that are initially added. For instance, metal ions (of, e.g., a detergent) can migrate to other acidic or anionic sites of other molecules. The products formed thereby, including the products formed upon employing the composition of the present invention in its intended use, may not be susceptible of easy description. Nevertheless, all such modifications and reaction products are included within the scope of the present invention; the present invention encompasses the composition prepared by admixing the components described above.

Each of the documents referred to above is incorporated herein by reference, including any prior applications, whether or not specifically listed above, from which priority is claimed. The mention of any document is not an admission that such document qualifies as prior art or constitutes the general knowledge of the skilled person in any jurisdiction. Except in the Examples, or where otherwise explicitly indicated, all numerical quantities in this description specifying amounts of materials, reaction conditions, molecular weights, number of carbon atoms, and the like, are to be understood as modified by the word “about.” It is to be understood that the upper and lower amount, range, and ratio limits set forth herein may be independently combined. Similarly, the ranges and amounts for each element of the invention can be used together with ranges or amounts for any of the other elements.

While certain representative embodiments and details have been shown for the purpose of illustrating the subject invention, it will be apparent to those skilled in this art that various changes and modifications can be made therein without departing from the scope of the subject invention. In this regard, the scope of the invention is to be limited only by the following claims. 

1. A lubricating composition comprising: an oil of lubricating viscosity; and 2 to 20 wt % of a dispersant additive package including: an acylated poly(1-olefin)-based dispersant, where the poly(1-olefin) is comprised of at least 75 mole percent of a C₆ to C₁₈ hydrocarbyl; a polyisobutylene-based dispersant; where the ratio of the acylated poly(1-olefin)-based dispersant to the polyisobutylene succinimide dispersant is from 3:1 to 1:3, or 2:1 to 1:2, or 3:2 to 2:3.
 2. The lubricating composition of claim 1, wherein the poly(1-olefin) comprises at least 80 mole percent of the C₆ to C₁₈ hydrocarbyl.
 3. The lubricating composition of claim 1, wherein the 1-olefin comprises at least 90 mole percent of the C₆ to C₁₈ hydrocarbyl.
 4. The lubricating composition of claim 1, wherein the 1-olefin comprises at least 95 mole percent of the C₆ to C₁₈ hydrocarbyl.
 5. The lubricating composition of claim 1, wherein the 1-olefin comprises 100 mole percent of the C₆ to C₁₈ hydrocarbyl.
 6. The lubricating composition of claim 1, wherein the 1-olefin is a C₈ to C₁₂ hydrocarbyl.
 7. The lubricating composition of claim 1, wherein the acylated poly(1-olefin)-based dispersant is selected from a polyalphaolefin succinimide, a polyalphaolefin succinamide, a polyalphaolefin acid ester, a polyalphaolefin oxazoline, a polyalphaolefin imidazoline, a polyalphaolefin succinamide imidazoline, and combinations thereof.
 8. The lubricating composition of claim 1, wherein the acylated poly(1-olefin)-based dispersant is a polydecene succinimide.
 9. The lubricating composition of claim 1, wherein the poly(1-olefin) from which the acylated poly(1-olefin)-based dispersant is derived has a number average molecular weight of from 400 to 10,000.
 10. The lubricating composition of claim 1, wherein the acylated poly(1-olefin)-based dispersant is an acylated polydecene succinimide where the polydecene from which the acylated polydecene succinimide is derived has a number average molecular weight of from 400 to 10,000.
 11. The lubricating composition of claim 1, wherein the acylated poly(1-olefin)-based dispersant has a TBN of from 3 to 50, or 5 to 20, or 10 to
 30. 12. The lubricating composition of claim 1, wherein the polyisobutylene-based dispersant is a polyisobutylene succinimide.
 13. The lubricating composition of claim 1, wherein the polyisobutylene from which the polyisobutylene succinimide is derived has a number average molecular weight of from 500 to 3,000.
 14. The lubricating composition of claim 1, wherein the polyisobutylene succinimide dispersant has a TBN of from 5 to 50, or 10 to 40, or 15 to
 30. 15. The lubricating composition of claim 1, wherein the TBN of the total lubricating composition is from 4 to 14 mg KOH/g.
 16. The lubricating composition of claim 1, further comprising an additive selected from a detergent, an antiwear agent, an antioxidant, and combinations thereof.
 17. The lubricating composition of claim 1, wherein the dispersant additive package comprises from 2 to 10 wt % of the lubricating composition.
 18. The lubricating composition of claim 1, wherein the dispersant additive package comprises from 4 to 8 wt % of the lubricating composition.
 19. The lubricating composition of claim 1, wherein the lubricating composition has a kinematic viscosity at 100° C. from 5 to 12 cSt (mm²/s) and a kinematic viscosity at 40° C. from 40 to 50 cSt (mm²/s).
 20. The lubricating composition of claim 1, wherein the lubricating composition has a kinematic viscosity at 100° C. from 6 to 10 cSt (mm²/s) and a kinematic viscosity at 40° C. from 40 to 47 cSt (mm²/s).
 21. The lubricating composition of claim 1, wherein the lubricating composition has a high temperature, high shear viscosity (HTHS) of less than 3 mPa-s, or less than 2.6 mPa-s, or less than 2.1 mPa-s as measured at 150° C. per ASTM D4683.
 22. The lubricating composition of claim 1, wherein the dispersant additive package comprises: 1 to 19 wt % of the acylated poly(1-olefin)-based dispersant; and 1 to 19 wt % of the polyisobutylene-based dispersant.
 23. The lubricating composition of claim 1, wherein the dispersant additive package comprises: 0.3 to 1 wt % of the acylated poly(1-olefin)-based dispersant; and 0.1 to 3 wt % of the polyisobutylene succinimide dispersant.
 24. The lubricating composition of claim 1, wherein the dispersant additive package comprises: 0.9 to 2.5 wt % of the acylated poly(1-olefin)-based dispersant; and 0.3 to 7.5 wt % of the polyisobutylene succinimide dispersant.
 25. The lubricating composition of claim 1, wherein the dispersant additive package comprises: 1.5 to 3 wt % of the acylated polydecene succinimide dispersant; and 0.5 to 9 wt % of the polyisobutylene succinimide dispersant.
 26. The lubricating composition of claim 1, wherein the dispersant additive package comprises: 1.5 to 3 wt % of the acylated polydecene succinimide dispersant; and 0.5 to 9 wt % of the polyisobutylene succinimide dispersant.
 26. The lubricating composition of claim 1, wherein the dispersant additive package comprises: 1.9 to 3.8 wt % of the acylated polydecene succinimide dispersant; and 1.3 to 3.1 wt % of the polyisobutylene succinimide dispersant.
 27. The lubricating composition of claim 1, wherein: the dispersant packing includes: 2 to 8 wt % of a polydecene succinimide dispersant; 1 to 6 wt % of a polyisobutylene succinimide dispersant, and the ratio of the polydecene succinimide dispersant to the polyisobutylene dispersant is from 2:1 to 1:2, wherein the lubricating composition has a kinematic viscosity at 100° C. from 6 to 10 cSt (mm²/s) and a kinematic viscosity at 40° C. from 40 to 47 cSt (mm²/s) and a high shear viscosity (HTHS) of less than 3 mPa-s.
 28. A method for lubricating an internal combustion engine comprising: supplying to an internal combustion engine a lubricating composition according to claim
 1. 29. The method of claim 27, wherein the internal combustion engine is a turbo-charged direct injection engine. 